In an Ideal Biosphere Reserve, Like the One in the Illustration

In an ideal biosphere reserve, like the one in the illustration, what activities occur in the central (darkest) area?

A) Only animals are allowed; human activity is prohibited.
B) Development is concentrated in order to minimize its impact in the outer margins.
C) Animal monitoring and research are allowed.
D) Educational programs, low-impact development, and ecotourism activities are allowed.
E) Sustainable agriculture and high-impact tourism are allowed.